Re: [Xen-devel] [PATCH v5 12/17] xen/arm: p2m: Remove unused operation ALLOCATE

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Tue, 28 Jun 2016, Julien Grall wrote:
> The operation ALLOCATE is unused. If we ever need it, it could be
> reimplemented with INSERT.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v4:
>         - Patch added
> ---
>  xen/arch/arm/p2m.c        | 67 
> ++---------------------------------------------
>  xen/include/asm-arm/p2m.h |  3 ---
>  2 files changed, 2 insertions(+), 68 deletions(-)
> 
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index fcc4513..f11094e 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -547,7 +547,6 @@ static int p2m_mem_access_radix_set(struct p2m_domain 
> *p2m, unsigned long pfn,
>  
>  enum p2m_operation {
>      INSERT,
> -    ALLOCATE,
>      REMOVE,
>      RELINQUISH,
>      CACHEFLUSH,
> @@ -667,7 +666,6 @@ static int apply_one_level(struct domain *d,
>  {
>      const paddr_t level_size = level_sizes[level];
>      const paddr_t level_mask = level_masks[level];
> -    const paddr_t level_shift = level_shifts[level];
>  
>      struct p2m_domain *p2m = &d->arch.p2m;
>      lpae_t pte;
> @@ -678,58 +676,6 @@ static int apply_one_level(struct domain *d,
>  
>      switch ( op )
>      {
> -    case ALLOCATE:
> -        ASSERT(level < 3 || !p2m_valid(orig_pte));
> -        ASSERT(*maddr == 0);
> -
> -        if ( p2m_valid(orig_pte) )
> -            return P2M_ONE_DESCEND;
> -
> -        if ( is_mapping_aligned(*addr, end_gpaddr, 0, level_size) &&
> -           /* We only create superpages when mem_access is not in use. */
> -             (level == 3 || (level < 3 && !p2m->mem_access_enabled)) )
> -        {
> -            struct page_info *page;
> -
> -            page = alloc_domheap_pages(d, level_shift - PAGE_SHIFT, 0);
> -            if ( page )
> -            {
> -                rc = p2m_mem_access_radix_set(p2m, paddr_to_pfn(*addr), a);
> -                if ( rc < 0 )
> -                {
> -                    free_domheap_page(page);
> -                    return rc;
> -                }
> -
> -                pte = mfn_to_p2m_entry(page_to_mfn(page), mattr, t, a);
> -                if ( level < 3 )
> -                    pte.p2m.table = 0;
> -                p2m_write_pte(entry, pte, flush_cache);
> -                p2m->stats.mappings[level]++;
> -
> -                *addr += level_size;
> -
> -                return P2M_ONE_PROGRESS;
> -            }
> -            else if ( level == 3 )
> -                return -ENOMEM;
> -        }
> -
> -        /* L3 is always suitably aligned for mapping (handled, above) */
> -        BUG_ON(level == 3);
> -
> -        /*
> -         * If we get here then we failed to allocate a sufficiently
> -         * large contiguous region for this level (which can't be
> -         * L3) or mem_access is in use. Create a page table and
> -         * continue to descend so we try smaller allocations.
> -         */
> -        rc = p2m_create_table(d, entry, 0, flush_cache);
> -        if ( rc < 0 )
> -            return rc;
> -
> -        return P2M_ONE_DESCEND;
> -
>      case INSERT:
>          if ( is_mapping_aligned(*addr, end_gpaddr, *maddr, level_size) &&
>             /*
> @@ -1169,7 +1115,7 @@ static int apply_p2m_changes(struct domain *d,
>          }
>      }
>  
> -    if ( op == ALLOCATE || op == INSERT )
> +    if ( op == INSERT )
>      {
>          p2m->max_mapped_gfn = max(p2m->max_mapped_gfn, egfn);
>          p2m->lowest_mapped_gfn = min(p2m->lowest_mapped_gfn, sgfn);
> @@ -1197,7 +1143,7 @@ out:
>  
>      spin_unlock(&p2m->lock);
>  
> -    if ( rc < 0 && ( op == INSERT || op == ALLOCATE ) &&
> +    if ( rc < 0 && ( op == INSERT ) &&
>           addr != start_gpaddr )
>      {
>          BUG_ON(addr == end_gpaddr);
> @@ -1212,15 +1158,6 @@ out:
>      return rc;
>  }
>  
> -int p2m_populate_ram(struct domain *d,
> -                     paddr_t start,
> -                     paddr_t end)
> -{
> -    return apply_p2m_changes(d, ALLOCATE, start, end,
> -                             0, MATTR_MEM, 0, p2m_ram_rw,
> -                             d->arch.p2m.default_access);
> -}
> -
>  int map_regions_rw_cache(struct domain *d,
>                           unsigned long start_gfn,
>                           unsigned long nr,
> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
> index 8a96e68..4752161 100644
> --- a/xen/include/asm-arm/p2m.h
> +++ b/xen/include/asm-arm/p2m.h
> @@ -141,9 +141,6 @@ mfn_t p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t 
> *t);
>  /* Clean & invalidate caches corresponding to a region of guest address 
> space */
>  int p2m_cache_flush(struct domain *d, gfn_t start, unsigned long nr);
>  
> -/* Setup p2m RAM mapping for domain d from start-end. */
> -int p2m_populate_ram(struct domain *d, paddr_t start, paddr_t end);
> -
>  int map_regions_rw_cache(struct domain *d,
>                           unsigned long start_gfn,
>                           unsigned long nr_mfns,
> -- 
> 1.9.1
> 

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